Khan.scratchpad.disable(); Michael sells magazine subscriptions and earns $$3$ for every new subscriber he signs up. Michael also earns a $$27$ weekly bonus regardless of how many magazine subscriptions he sells. If Michael wants to earn at least $$78$ this week, what is the minimum number of subscriptions he needs to sell?
Solution: To solve this, let's set up an expression to show how much money Michael will make. Amount earned this week $=$ $ $ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus Since Michael wants to make at least $$78$ this week, we can turn this into an inequality. Amount earned this week $\geq $78$ Subscriptions sold $\times$ Price per subscription $+$ Weekly bonus $\geq $78$ We are solving for the number of subscriptions sold, so let subscriptions sold be represented by the variable $x$ We can now plug in: $x \cdot $3 + $27 \geq $78$ $ x \cdot $3 \geq $78 - $27 $ $ x \cdot $3 \geq $51 $ $x \geq \dfrac{51}{3} = 17$ Michael must sell at least 17 subscriptions this week.